Paleontologists have long puzzled over why the genus Tyrannosaurus, which included a number of species, e.g., Tyrannosaurus rex, always had relatively tiny forelegs/hands, right up until the catastrophic end of the Cretaceous period/Mesozoic era, Their size relative to their owners suggests that they were the result of a slow evolutionary process of eliminating them entirely, yet they were possessed by all Tyranosaurids beginning with the very first Tyrannosaurs, continuing through 3-5 million years, generation after generation, species after species, culminating in the last of the species, Tyrannosaurus rex.

Since that feature -- the tiny arms -- of the Tyrannosaurs was so persistent among all the members of that genus, the conclusion is that tiny or not, those arms were good for *something*, else they'd have eventually evolved out of existence. But what?

Dr. Robert T. "Dinosaur Bob Bakker points out that there is clear evidence that, barring accidental death, death from disease, and so on, at least some Tyrannosaurs outlived by several years their ability to feed themselves and get around for any reason. By age 27 or so, due to its great weight and consequent wear and tear on its body, probably complicated by cumulative breaks and sprains as well as arthritis, a Tyrannosaur was not able to catch prey. defend itself, or otherwise do all the things needed for its survival. Yet some of them, at least, lived to 35. How?

The tyrannosaurs lived with close relatives -- children, nieces, nephews, grandchildren, etc. -- who took care of them and provided them with food. They loved their elders, respecting their wisdom and loving them for the care and protection those elders have them when they were relatively young. Thus they lived in family groups, cooperating with one another when it came to acquiring food, driving away rivals, and other necessary tasks, rather like we primates. And like many primates, they might well have groomed one another, squeezing the skin of other members of their clans to force parasites to emerge from tunnels in the Tyrannosaurs' skin so that they could be smashed or even eaten by groomers. Chimpanzees, our closest relatives, do that. And like chimps, tyrannosaurs had social smarts.

So those "pitifully small" Tyrannosaur arms may well have been used fir grooming one another, a quintessentially social behavior. That implies their intelligence was a good deal greater than many give them credit for, If we could bring some T, rexes from the Cretaceous forward in time to now, we might even be able to make friends with them and share knowledge with them.